1. Field of the Invention
The present invention relates to a video signal processing system including a scaler and a vertical blanking interval (VBI) decoder, and more particularly, to a controller for effectively processing scaler data and VBI data using a scaler memory.
2. Description of the Related Art
FIG. 1 is a block diagram of a typical scaler for scaling video signals by a predetermined ratio. First and second line memory units 10 and 12, each of which has two line memories, receive luminance data Y and chrominance data C to delay at most two lines. A vertical scaler 14 receives luminance data Y, YD and YDD output by the first line memory unit 10 and chrominance data C, CD and CDD output by the second line memory unit 12, and then vertically scales the received data and performs filtering for extracting effective lines and improving the screen quality. A horizontal scaler 16 receives luminance data YZ and chrominance data CZ output by the vertical scaler 14, and then horizontally scales the received data to output scaled data YOUT and COUT.
Meanwhile, in a video signal processing system, there are many devices such as a VBI decoder which allows predetermined data to be output during vertical blanking interval (VBI). The VBI decoder outputs serially VBI data such as closed caption data, teletext data and SMPTE time code data etc, through another external pin during VBI. Thus, the additional external pin is required to output and process the VBI data.
A need therefore exists for a scaler memory controller of a video signal processing system including a scaler and VBI decoder, in which active video data is processed in an active interval and vertical blanking data is processed in a vertical blanking interval (VBI), using a scaler memory.
There also exists a need to provide a scaler memory controller of a video signal processing system including a scaler and a VBI decoder, in which active video data and vertical blanking data are time-division read or written from or to the scaler memory.
A further need exists to provide a method for controlling a scaler memory for processing active video data and vertical blanking data using a scaler memory, in a video signal processing system including a scaler and a VBI decoder.